Phylogenetic tree showing sequences of the coding region of Gamma coronaviruses and Delta coronavirus N protein. Nucleotide neighbor-joining distance tree (Tamura 3-parameter substitution model) for partial N gene sequence (407 bp). Strains detected in the present study are preceded by black triangles. The numbers at each node are bootstrap values greater than 70 from 500 replicates. The bar represents the number of substitutions per site.